The Trijicon SA36 Smith&Wesson 1911 3 Dot Night Sights will not fit a Rock Island Armory 1911A1. Your 1911 uses a Novak sight cut and would need Trijicon SA35 Novak .45/.40/35mm 3 Dot Night Sights, found by using the link below:
https://www.opticsplanet.com/trijicon-sa35-novak-45-40-35mm-3-dot-front-rear-night-sight-set.html